Alteration of cation and water balance in cataractous lenses is well known. Previous studies have established the prominet role of a cation pump in the lens epithelium in maintaining cation balance. It is clear that there is a balance between the active cation pump and passive leak pathways. We plan to perform detailed electrical and ion flux experiments to quantitate these parameters so that the observed cation balance and distribution within the lens may be explained. Our analyses will take into account the possible difference between passive permeability at the anterior and posterior lens surfaces, and the lens resting potential, which includes an electrogenic component. By examining 1) the effect of various agents on the electrogenic component of the lens potential and 2) changes in lens epithelium cyclic AMP levels under various conditions, we will investigate the possible role of cyclic AMP in the intrinsic regulation of the lens cation pump. Using an established animal model, the time course of alterations in cation transport ad permeability will be compared to morphological changes during the development of cataract.